Administration devices or self-administration devices can be used to serve diabetes patients. An administration device for the self-administration of medicines such as insulin may be placed in a patient's pocket and connected to the patient's organism to supply a suitable dose of medicine, in particular insulin, to the patient. The user interface provided for the patient can consist of a display, keys and/or buttons for entering instructions for a control circuit included in the device. Via the user interface, the administration device may be programmed to allow for information such as the administration history or the remaining medicine amount in a medicine reservoir to be recalled and allow for the administration of medicine boli to be initiated.
However, since the administration device can work automatically through the control of a control device such as a micro controller, it may not be necessary for the display to be constantly active. Furthermore, the display may require a lot of electrical energy, hence if the display is in operation for a long time, it may be necessary to include large batteries or accumulators in the device. Accordingly, an attempt should be made to activate a display only when it is needed.
In some devices, the function of activating the display can be performed via a dedicated button. However, providing the additional button may be an obstacle to minimize the size of the overall device. Alternatively, the display may be activated whenever any button or key is pressed, thus potentially increasing the power consumption of the display.
Administration devices, such as those used in diabetes therapy, can be carried concealed from view such as by storing them in a trousers pocket. Furthermore, these administration devices can be programmed and/or manipulated by pressing keys or buttons through the trousers fabric based on audible and/or tactile feedback signals provided by the administration device. This may allow the patient to operate the device and in particular to initiate the administration of medicine boli with the device being concealed from view. If the device is operated in this way, activating the display may be unnecessary.
However, since concealable administration devices can be carried in a clothes pocket, such as a trousers pocket, as described above, it is possible that the keys or buttons become activated through arbitrarily and unintended bumping which may result in, among others things, an unintended administration of medicine doses. In this context, it has to be taken into account that an administration device has to administer a number of pre-adjustable doses, so-called basal doses, which have to be administered in accordance with the therapeutic needs of the patient according to a predefined schedule in a substantially continuous way. In addition, the patient may typically need additional doses, so called bolus doses, depending on particular circumstances and events which will vary from day to day, such that as the correction of high blood glucose values or food intake. Thus, the administration device may allow for the administration of such additional doses in an easy and discrete way, using the buttons or keys which are provided in order to operate the device. To prevent the unintended administration of medicine doses which may cause severe medical consequences due to buttons or keys being pressed unintentionally, for example by a key carried in the same pocket as the device, prior-art administration devices can be provided with at least two keys or buttons which have to be operated in sequence and within a particular time in order to administer a bolus dose. This, however, can increase the operational complexity and decrease the user comfort in particular if the administration device is operated concealed from view.
Conversely, administration can unintentionally occur if a button becomes instable due to a defect, e.g. has a loose connection or contact element since this again may cause a large number of unintended operations of a the unstable button, resulting in the administration of a large unintended dose with all its negative consequences. Occurrence of this situation may be prevented by providing at least too buttons which have to be operated in sequence as described above.